DENVER (AP) -- A new study
shows chronic wasting disease can spread through environmental contamination
and not just animal-to-animal contact, a finding that could change the
way experts fight the ailment.

The study, published in the online edition of the journal
Emerging Infectious Diseases, also suggests that chronic wasting outbreaks
could last longer than previous models projected.

The study confirms a long-held theory that deer and elk
can contract the fatal disease through land contaminated by the carcasses
or excrement of infected animals.

"The experimental findings show that we need to
consider several potential exposure routes when attempting to control this
disease," said University of Wyoming professor Elizabeth Williams,
a co-author of the report.

Previous projections on how the disease would spread
were based only on animal-to-animal transmission. Those models predicted
the disease would begin to decline once the number of infected animals
dropped.

The new study suggest the rate of decline could be much
slower.

In the experiment, researchers confined three sets of
healthy deer in separate paddocks. In one paddock they included a live
deer infected with chronic wasting disease, in another they included carcasses
with the disease and the third paddock had previously contained infected
deer.

In each paddock, some of the healthy deer contracted
the disease.

The researchers said infection rates in their experiment
may be higher than in the wild because of the enclosed environment, but
conditions simulated the wild.

"Although live deer and elk still seem the most
likely way for CWD to spread geographically, our data show that environmental
sources could contribute to maintaining and prolonging local epidemics,
even when all infected animals are eliminated," said Colorado Division
of Wildlife veterinarian Michael Miller, another report co-author.

Chronic wasting creates sponge-like holes in the brains
of deer or elk, causing the animal to grow thin, act abnormally and die.
It is a prion disease, similar to mad cow disease.

There never has been a known case of it being transferred
to humans or livestock, but people are cautioned not to eat the brain,
nervous tissue or lymph glands of the animals.

The disease has been found in a dozen U.S. states and
Canada.

Study findings will also be published in the June issue
of Emerging Infectious Diseases.